1nal

THE THREE-DIMENSIONAL STRUCTURE OF N-ACETYLNEURAMINATE LYASE FROM ESCHERICHIA COLI


Cartoon representation of YagE tetramer showing the 2-fold symmetry axes between monomers. Chains A, B , C , and D are colored cyan , lime , magenta , and yellow , respectively (2v9d). Superposition of YagE monomer (cyan) with EcNAL (1nal, yellow ), SsKDGA (1w3i, <font color='magenta'>magenta ), <scene name='2v9d/Alignment/10'>EcDHDSP (1xky, <font color='lime'>lime ), and <scene name='2v9d/Alignment/11'>BaDHDPS (2ats, <font color='blue'>blue ) monomers. Although YagE possesses only 23, 24, and 27% sequence identity with EcNAL, SsKDGA, EcDHDPS, respectively, their monomeric structures are all very similar. Superposition of active site residues of YagE with <scene name='2v9d/Active_site1/1'>SsKDGA (<font color='magenta'>magenta, 1w3i), <scene name='2v9d/Active_site1/2'>BaDHDPS (<font color='blue'>blue , 2ats), and <scene name='2v9d/Active_site1/3'>EcNAL (<font color='black'>yellow , 1nal), residues are labeled according to the corresponding PDB structures. Members of the NAL protein subfamily have very similar active sites and a single amino acid substitution can significantly change their function. For example, NAL (1nal) gets DHDPS activity by substitution of a <scene name='2v9d/Leucine142/2'>leucine <font color='orange'>(orange) to <scene name='2v9d/Arginine142/2'>arginine <font color='blue'>(blue) at position 142. The possible active site region of <font color='cyan'>YagE demonstrates closest sequence similarity to the active site of <font color='magenta'>KDG aldolase of SsKDGA (1w3i) and <font color='black'>NAL of EcNAL (1nal) (yellow), suggesting that this protein can perform either of these functions. Although the active site of EcDHDPS (1xky) and BaDHDPS (2ats) shows similarities, the important residue that differentiates between NAL and DHDPS, namely Leu142 (in 1nal), is also present in YagE <scene name='2v9d/Leucine150/2'>(Leu150) <font color='cyan'>(labeled cyan) at that particular position suggesting that YagE performs a NAL-related function rather than DHDPS-related one.

About this Structure
1NAL is a 4 chains structure of sequences from Escherichia coli. Full crystallographic information is available from OCA.